Facile Ar−CF3 Bond Formation at Pd. Strikingly Different Outcomes of Reductive Elimination from (Ph3P)2Pd(CF3)Ph and (Xantphos)Pd(CF3)Ph

Facile and highly selective perfluoroalkyl-aryl reductive elimination from a metal center (Pd) has been demonstrated for the first time. At temperatures as low as 50-80 degrees C, (Xantphos)Pd(Ph)CF3 undergoes remarkably clean decomposition to produce CF3Ph in high yield and selectivity. In contrast, analogous trifluoromethylpalladium aryls stabilized by rigid cis-chelating ligands such as dppe are completely unreactive at temperatures up to 130-140 degrees C. Decomposition of (Ph3P)2Pd(Ph)CF3 in the presence of PhI in benzene at 60 degrees C does not produce PhCF3 but rather leads to (Ph3P)2Pd(Ph)I and Ph4P+(Ph3P)Pd(CF3)3- in a 2:1 ratio with high selectivity.